This invention relates to a device which comprises a plurality of Hall elements and is designed to determine the sum of, or the difference between, the voltages between all of the adjacent Hall elements.
FIG. 1 shows the arrangement of a conventional Hall element device comprising two Hall elements H1 and H2. One Hall element H1 comprises a first control current-supplying terminal CT11, a second control current-supplying terminal CT12, a first output terminal OT11 and a second output terminal OT12. The other Hall element H2 comprises a first control current-supplying terminal CT21, a second control current-supplying terminal CT22, a first output terminal OT21 and a second output terminal OT22. The first control current-supplying terminal CT11 of the Hall element H1 and the first control current-supplying terminal CT21 of the Hall element H2 are connected to a common power source PS through the corresponding constant current sources I1 and I2. The second control current-supplying terminals CT12 and CT22 of the respective Hall elements H1 and H2 are grounded. The second output terminal OT12 of the first Hall element H1 and the first output terminal OT21 of the second Hall element H2 are connected together by a resistor R. A Hall voltage Vh is produced across the first output terminal OT11 of the first Hall element H1 and the second output terminal OT22 of the second Hall element H2.
Whenever the second output terminal OT12 of the first Hall element H1 and the first output terminal OT21 of the second Hall element H2 of the conventional Hall element device described above have the same potential, current does not run through the resistor R. Whenever the second output terminal OT12 and the second output terminal OT21 have different potentials, then current flows through the resistor R, leading to errors in the measurement carried out by the conventional Hall element device.
A Hall element of FIG. 2 has already been proposed to eliminate the above-mentioned drawback. With this proposed Hall element device, a first Hall element H1 is provided with an independent power source PS1, and a second Hall element is similarly provided with an independent power source PS2. The second output terminal OT12 of the first Hall element H1 and the first output terminal OT21 of the second Hall element H2 are directly connected together. However, the provision of electrically isolated power sources PS1 and PS2 for the first and second Hall elements H1 and H2, respectively, complicates the arrangement of a resultant Hall element device and is uneconomical. Further, the provision of such isolated power sources PS1 and PS2 is accompanied with the drawback that noise readily occurs due to a parasitic capacity being produced across the power sources PS1 and PS2.